Frequencies for first 10,000 rows of a2 variable in midrvacc dataset :

         a2 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,464       64.64       64.64
          1 |         47        0.47       65.11
          2 |         64        0.64       65.75
          3 |         79        0.79       66.54
          4 |         75        0.75       67.29
          5 |         86        0.86       68.15
          6 |         94        0.94       69.09
          7 |        100        1.00       70.09
          8 |         98        0.98       71.07
          9 |        101        1.01       72.08
         10 |        138        1.38       73.46
         11 |        163        1.63       75.09
         12 |        141        1.41       76.50
         13 |        160        1.60       78.10
         14 |        151        1.51       79.61
         15 |        170        1.70       81.31
         16 |        168        1.68       82.99
         17 |        171        1.71       84.70
         18 |        160        1.60       86.30
         19 |        170        1.70       88.00
         20 |        144        1.44       89.44
         21 |        138        1.38       90.82
         22 |        160        1.60       92.42
         23 |        121        1.21       93.63
         24 |        123        1.23       94.86
         25 |         90        0.90       95.76
         26 |         73        0.73       96.49
         27 |         62        0.62       97.11
         28 |         70        0.70       97.81
         29 |         42        0.42       98.23
         30 |         36        0.36       98.59
         31 |         31        0.31       98.90
         32 |         18        0.18       99.08
         33 |         18        0.18       99.26
         34 |         12        0.12       99.38
         35 |          7        0.07       99.45
         36 |         11        0.11       99.56
         37 |          6        0.06       99.62
         38 |          8        0.08       99.70
         39 |          6        0.06       99.76
         40 |          2        0.02       99.78
         42 |          7        0.07       99.85
         43 |          2        0.02       99.87
         44 |          2        0.02       99.89
         45 |          3        0.03       99.92
         46 |          2        0.02       99.94
         47 |          3        0.03       99.97
         48 |          1        0.01       99.98
         49 |          1        0.01       99.99
         51 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016